Rename OGR OGDI driver as OGR_OGDI
GDALDataset: replace CPLHashSet by std::map for better efficiency
Add GDALOpenSharedInternal() to be used by OGROpenShared()
Fix failures in ogr_refcount.py
Remove deprecated and unused GDALProjDefH and GDALOptionDefinition types
Add GDAL_DCAP_RASTER and GDAL_DCAP_VECTOR
Make OGRDataSource, OGRSFDriver and OGRSFDriverRegistrar even more lighter